﻿/*
*    Qizx/open 3.0 beta
*
* This code is the open-source version of Qizx.
* Copyright (C) 2004-2009 Axyana Software -- All rights reserved.
*
* The contents of this file are subject to the Mozilla Public License 
*  Version 1.1 (the "License"); you may not use this file except in 
*  compliance with the License. You may obtain a copy of the License at
*  http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
*  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
*  for the specific language governing rights and limitations under the
*  License.
*
* The Initial Developer of the Original Code is Xavier Franc - Axyana Software.
*
*/
using System;
using EvaluationException = System.Qizx.Api.EvaluationException;
using EvalContext = System.Qizx.XQuery.EvalContext;
using ExprDisplay = System.Qizx.XQuery.ExprDisplay;
using Focus = System.Qizx.XQuery.Focus;
using ModuleContext = System.Qizx.XQuery.ModuleContext;
using XQType = System.Qizx.XQuery.XQType;
using System.Qizx.Api;
using System.Qizx.Xdm;

namespace System.Qizx.XQuery.Op {
    class AssignExpr : VarClause {
        private GlobalVariable global;

        public AssignExpr(QName variable, Expression expr)
            : base(variable) {
            this.expr = expr;
        }

        public void dump(ExprDisplay d) {
            d.header(this);
            d.property("variable", "$" + variable + " : " + declaredType
                       + (d.Pretty ? "" : " addr "
                           + (varDecl != null ? ("" + varDecl.address) : "?")));
            d.child(expr);
        }

        public override Expression StaticCheck(ModuleContext context, int flags) {
            // FIXME what if assigning a var in outer closure?
            varDecl = context.lookforLocalVariable(variable);
            if (varDecl != null) {
                varDecl.offset = this.offset;
                // TODO check variable declaration: assignable etc
            } else { // is it a global ?
                global = context.lookforGlobalVariable(variable);
                if (global == null)
                    context.error("XPST0008", this,
                                  "variable " + context.PrefixedName(variable) + " not declared");
            }

            expr = context.staticCheck(expr, 0);

            return this;
        }

        public override XQValue eval(Focus focus, EvalContext context) {
            if (varDecl != null) {
                context.storeLocal(varDecl, expr, null, false, focus, context);
            } else {
                XQValue value = expr.eval(focus, context);
                context.setGlobal(global, value);
            }
            return XQValues.Empty;
        }
    }
}